Abstract: Altering tables in a database system may be difficult because the tables may only be altered when all connection to the tables have been released. A free resources parameter may be set on in a management system for the database system to specify that resources should be attempted to be released. Connections to the database may be closed earlier than conventionally closed. For example, connections that are idle may be released. Once the connections have been released the database may be altered and the free resources parameter turned off. The free resources parameter notifies the database system of a pending alteration and allows the database to gracefully close connections to provide an opportunity for the alteration to occur.

Abstract: Performance of database systems may be improved by reducing the processing performed with each database query. For example, when a database query, such as a SQL statement, is executed with a first set of values, the query may be stored as a prepared statement and parsed and optimized as a section. When a similar database query is executed with a new set of values the section may be re-executed with the new set of values without re-parsing or re-optimizing the prepared statement. A similar database query may continue to be executed with new sets of values until the section is invalid because of an alteration to the table definitions of the database schema.

Abstract: A system and apparatus for detecting the approach of a vehicle includes an encoded signal which identifies a vehicle or route, and which is used to distinguish from different vehicles and routes. A receiver detects transmission signals above a threshold level, and responsive to reception thereof checks for one or a plurality of codes that identify particular vehicles of interest. When a desired signal is received, an alarm or indicator is generated that alerts a person. When the indicator is terminated, a lock-out period prevents undesired re-activation of the alarm or indicator based upon the same code. Unique headers enable transmission and exchange of additional data, and logical text may be provided which enables more ready viewing of coded information. The present invention has industrial applicability to public and private transportation systems, whether for passengers or other cargo.